Airborne Escherichia coli (E. coli) originating in poultry houses can be transmitted outside poultry farms through the air, posing risks of barn-to-barn infection through airborne transmission. The objective of this study is to examine the effect of ultraviolet (UV) light on the inactivation of airborne E. coli carried by poultry dust particles under laboratory conditions. A system containing two chambers that were connected by a UV scrubber was designed in the study. In the upstream chamber of the system, airborne E. coli attached to dust particles were aerosolized by a dry aerosolization-based system. Two sets of air samplers were placed in the two chambers to collect the viable airborne E. coli. By comparing the concentration of airborne E. coli in the two chambers, the inactivation rates were calculated. The airborne E. coli inactivation rates were tested at different contact times with the aid of a vacuum pump (from 5.62 to 0.23 s of contact time) and different UV irradiance levels (of 1707 µW cm-2 and 3422 µW cm-2). The inactivation rates varied from over 99.87% and 99.95% at 5.62 s of contact time with 1707 µW cm-2 and 3422 µW cm-2 of UV irradiance to 72.90% and 86.60% at 0.23 s of contact time with 1707 µW cm-2 and 3422 µW cm-2 of UV irradiance. The designed system was able to create the average UV irradiation of 1707 µW cm-2 and 3422 µW cm-2 for one UV lamp and two UV lamps, respectively. The findings of this study may provide an understanding of the effect of UV light on the inactivation of airborne E. coli carried by dust particles and help to design an affordable mitigation system for poultry houses.
Keywords: airborne E. coli; barn-to-barn infection; dry aerosolization; poultry houses; ultraviolet radiation.